The present invention relates generally to the field of telecommunications and related systems. More particularly, the invention is directed to a method for initiating a feature request during an active telephone call.
As known in the prior art, there are many service features that could be of use during an active telephone call. These features include, for example, adding another party, obtaining operator services, transferring a call, reporting a trouble condition and changing the connection""s transmission characteristics. However, in today""s person-to-person connections there are no convenient methods of requesting those services once the call is in place.
One method of signaling to the telephone network that a new feature is desired is by using the TOUCH-TONE transmitters (dual-tone multifrequency (DTMF) signaling) built into the majority of telephone sets used in North America and in many telephone sets throughout the world.
Most telephone networks can easily recognize those DTMF signals and the digits transmitted can be interpreted as a code for the service requested.
The problem with using DTMF signaling to request network features during an active call is that so many other network and non-network devices make use of DTMF signals. There are few industry standards constraining how DTMF signals are used once the network connection is established. For example, voice-mail systems, answering machines and numerous other command responsive devices use their own proprietary DTMF commands to control their password, playback functions and/or control functions. If a network were using DTMF signals to initiate some of the network features noted above (call transfers, trouble reports and the like) there is a good possibility it would misinterpret DTMF signals intended for voice-mail systems.
Requiring longer strings of DTMF digits to initiate network feature requests would reduce the probability of network confusion at the expense of more complicated, and thus costly, command parsing circuitry. Moreover, a departure from the present and well established use of DTMF digits would in all likelihood render obsolete large numbers of installed voice-mail systems and other such devices. Furthermore, requiring the use of long strings of DTMF digits would be inconvenient to remember and is counter to friendliness that technology should strive to provide.
Another approach to initiating service features is through spoken word commands. Speech recognition is advancing as a technology and might be considered by some as a viable way of initiating feature requests in the middle of a call. In theory, a spoken command such as xe2x80x9cConnect us to the Operatorxe2x80x9d could trigger a special network action. Unfortunately, the accuracy of today""s speech recognition technology is still not high. If the spoken commands were short, the network might easily confuse it with similar, but different speech phrases. Furthermore, no matter what command is used, there is the very real possibility that the command phrase would occur in actual conversations without the speaker actually wanting the network to take action.
Selecting longer spoken phrases as triggers would reduce the probability of false detection, but would increase the probability that the network would not recognize the command due to the speaker""s unique diction, timing or accent, or due to transmission distortion in the network. Using longer commands would also greatly increase the complexity and cost of the signal processing needed for the command recognition. Longer phrases would also be more difficult to remember.
Flashing the switchhook on the telephone set is a conventional method for requesting a mid-call change in telephony features. Unfortunately, switchhook flashes are not propagated through the first network switch or PBX. Thus, a downstream network provider, such as an interexchange carrier, cannot use switchhook flashes to trigger feature requests.
U.S. Pat. No. 5,524,139 illustrates another approach to initiating additional telephone network features. This patent describes a system that a user deliberately calls and then trains on how to call other xe2x80x9cautomated telephonic information servicesxe2x80x9d (ATIS). In other words, if a telephone user routinely calls a certain DTMF-driven weather forecast from one ATIS and a particular set of stock quotes from a different ATIS, the system of the ""139 patent can be used to replace those two calls. The ""139 system can be xe2x80x9ctrainedxe2x80x9d to recognize simple specific spoken commands (like xe2x80x9cquote ATandT pricexe2x80x9d) and generate the necessary (and sometimes complex) DTMF sequences that will operate the downstream ATIS. After training, the user must call the ""139 system and give it the user""s personal voice and DTMF commands. The system can then run autonomously, perhaps dumping the results of its operations onto the user""s voice-mail system. Thus a system as proposed by the ""139 patent (a) requires a user to dial a particular number and cannot be initiated from within an arbitrary existing call, and (b) even though it uses both DTMF signals and speech recognition, it requires individualized user training in order to respond appropriately.
Accordingly, there is a great need in the art for an improved method of signaling to the network from within an existing telephone call that other features are desired.
Accordingly, it is an object of the present invention to obviate the above-noted shortcomings and disadvantages of prior art approaches to initiating feature requests in a telephone network.
It is a further object of the present invention to provide a method of initiating feature requests in a telephone network without imposing inconvenience to the user.
It is a still further object of the present invention to provide a method of initiating feature requests in a telephone network which is economical to implement and simple in operation.
It is a further object of the present invention to provide a method of initiating feature requests in a telephone network which is self-contained and is not reliant on outside systems for its operation.
It is a still further object of the present invention to provide a method of initiating feature requests in a telephone network which can be readily installed in existing telephone networks.